Please identify if each of the following is an example of a sample or a population.
All of the residents within New York city
A group of 150 high school students are selected from a high school of 400
Every fifth house within a city is selected to participate in a community survey
All of the police officers in the state of Ohio
300 students are surveyed from a college of 10,000
50 prisoners are selected from each of the 10 prisons within a state